1. Field of the invention
The present invention relates to a fuel supply system for use in heavy construction/forest equipment and a secondary fuel tank thereof, by which the heavy construction equipment, such as an excavator, driven at a spot where the supply of fuel is difficult or cumbersome or the forest equipment consuming a lot of fuel can effectively carry out the operation with the aid of the secondary fuel tank that is additionally installed in the equipment.
2. Description of the Prior Art
Heavy construction equipment is generally designed to have a capacity of a fuel tank on the standard of one day (about 16 hours). In case of the conventional heavy construction equipment, therefore, the capacity of the fuel tank determines the whole capacity of the fuel tank of the equipment. Existing excavators have an insufficient capacity of a fuel tank to supply the fuel required for a daily operation of heavy workload. An operator always carries a portable fuel tank filled with a fuel so as to prevent a fuel failure in supply. However, it is not a great help to the operator. That is, if the equipment runs short of fuels, the operator has to stop working so as to supply the fuel.
In case of up-countries or rugged sites, since it is difficult for a fuel supply vehicle to access the sites, the excavator should move to the place where the fuel can be supplied. After refueling, the excavator moves to the site. It causes not only the time loss, but the loss of efficiency, since the fuel is supplied during the work.
The conventional equipment includes a fuel line of series construction in which the fuel is fed from an existing fuel tank to an engine and the remaining fuel is returned to the fuel tank from the engine. In order to solve the above problem, Korean Patent No. 7055 discloses a fuel tank including an auxiliary fuel which is connected in series to a primary tank via a tube, by which the fuel is pumped from the auxiliary tank to the primary tank by a fuel supply pump. Since the auxiliary fuel tank is installed on a chassis portion of a lower driving structure, the tube should be detached from the auxiliary fuel tank after the fuel is fed to the primary fuel tank mounted on an upper swing structure. In addition, the capacity of the auxiliary fuel tank is not sufficient.